This invention relates to a resilient supporting device comprising a system of compartments filled with liquid and having flexible walls. More particularly, the invention relates to a resilient supporting device in the form of a mattress, cushion, pillow or the like.
A prior art liquid-filled supporting device of the above mentioned type is a waterbed mattress.
It is well known that the conventional waterbed mattresses suffer from the defect that there is a tendency for wave motions to be created in the water during use of the waterbeds. Such wave motions have a relatively long damping time and they may make the users of the waterbeds feel uncomfortable.
It has been attempted to reduce such undesired wave motions in waterbed mattresses by putting baffle plates inside the mattresses. Another solution of the same problem is disclosed in UK patent application No. 2.056.270 A which describes a waterbed mattress comprising a layer of open celled plastic foam partially submerged in the water provided within said mattress.
As disclosed in U.S. Pat. No. 3.810.265 it has also been attempted to dampen the wave motions in waterbed mattresses by adding to the water a viscosity increasing agent.
Another type of resilient supporting devices is disclosed in the published German patent application No. 30 31 777 A1 which describes i.a. a bicycle seat comprising two pads, each filled with a mixture of a flow reducing porous material (no examples of such a material are disclosed) and a viscous compressible mass consisting of air and a liquid (no examples of such liquid are disclosed).
The object of the invention is to provide a supporting device of the above mentioned type which, when loaded, produces a relatively low counter pressure during the initial loading phase and which counter pressure subsequently gradually increases to such a level that no further compression takes place.
Another object of the invention is to provide a resilient supporting device having liquid-filled compartments in which substantially no wave motion is generated during use.